The inter-relationship between the development of overweight and mental health problems is not well understood. Yet, understanding patterns of body weight development, and why some individuals are especially vulnerable to the accumulation of excess body weight may offer insight into causal mechanisms for the US obesity epidemic, and thus point towards avenues for combating epidemic trends. It also can be useful for early identification of high-risk individuals, and to tailor treatment strategies to be most appropriate for their specific patterns of risk. Conversely, if body weight adversely influences mental health development, the ongoing obesity epidemic raises concern for possible mental health implications. We propose to consider the inter-relationship between the development of body weight status and the development of specific mental health problems. Youth with emotional or behavioral dysregulation are predisposed to develop emotional mental health problems (e.g., mood disorders) and behavioral mental health problems (e.g., disruptive behavior disorder), respectively. We hypothesize that they may also be particularly vulnerable to weight gain. Conversely, overweight may increase depression risk, suggesting a possible reciprocal relationship that could lead to a cyclic pattern of worsening mental health and body weight status. Mental health concerns may thus increase individual susceptibility to an obesogenic environment, or act in synergy with environmental factors predisposing to weight gain (e.g. poverty, crime or other safety issues). We propose to examine such risk in the Pittsburgh Girls Study (PGS), a longitudinal community-based study of 2451 urban girls, currently aged 12 to 12 years, that was initiated to provide insight into the natural history of behavioral and emotional problems in girls. Focusing on this sample with high overweight risk (e.g., female; over half African American; frequent family poverty; and with home residences over-representing disadvantaged neighbor-hoods), can both provide etiologic insight and may highlight the most severe of both overweight and mental health outcomes. It is particularly important since individuals with lower socioeconomic status are frequently under-represented in health research. The project extends an ongoing and fruitful collaboration from Dr. McTigue's career development award on the role of environmental factors on weight development in the PGS. Combining insight from the rich PGS data on psycho-social development with that on weight-related behaviors, fitness, and body composition thus promises to provide unique and important insight into the development of weight-related health risk i US women. PUBLIC HEALTH RELEVANCE: object Narrative As overweight continues to rise among US adolescents, it is important to understand who has the highest risk of developing health problems related to their weight. This study will examine adolescent girls who are at high risk of overweight, to see whether certain underlying mental health problems may increase the rate of weight gain in adolescent girls, and, on the other hand, whether overweight also worsens mental health risk. We will draw inferences about possible long-term implications for the girls' health, as well as consider ways in which these findings may be used to improve identification and treatment of girls with high mental health or overweight risk.